Standardized Brazilian green propolis extract (EPP-AF®) enhances survival in a mouse model of sepsis induced by extraintestinal pathogenic Escherichia coli.

Sepsis represents a serious global public health issue, characterized by high mortality rates and complex treatment. This syndrome can be triggered by various pathogens, including extraintestinal pathogenic Escherichia coli (ExPEC), which produces numerous virulence factors, such as Pic, a serine protease capable of inducing lethal sepsis. This study aimed to investigate the therapeutic potential of a standardized Brazilian green propolis extract (EPP-AF®) in the treatment of sepsis induced by ExPEC. Swiss mice (6-8 weeks old) were infected with E. coli F5 and treated with EPP-AF® either prophylactically or therapeutically, at doses of 200 and 400 mg/kg. Following infection and treatment, the survival of the animals was monitored over five days. Biological samples (blood, peritoneal fluid, and organs) were collected to assess physiological parameters, bacterial counts in organs, serum markers, cell populations, and histopathological changes. Prophylactic treatment with EPP-AF® significantly increased the survival of septic animals and produced better effects than therapeutic treatment. EPP-AF® reduced bacterial loads in the peritoneal cavity, liver, and lungs. Treated animals did not exhibit histological damage to organs or alterations in red blood cell counts, platelet levels, or plasma protein concentrations. EPP-AF® also reduced cytokine levels in the peritoneal cavity and altered the serum leukocyte profile of septic animals. Furthermore, treated animals showed an increased number of peritoneal cells, which may have contributed to the reduced bacterial load in the peritoneum. Taken together, our results demonstrate that EPP-AF® enhances survival in septic animals through modulation of the immune response, indicating its strong potential as a pharmacological treatment for sepsis.